Protection circuit, power converter and protection control method

Abstract

The invention provides a protection circuit, a power converter and a protection control method.The protection circuit comprises a sampling circuit, a first trigger circuit, a controller and a logic gate circuit, and the sampling circuit is used for conducting current sampling on an energy storage inductor in a connected power conversion circuit and outputting a sampling signal; the first trigger circuit is used for outputting a wave-by-wave current-limiting trigger signal when a sampling signal characterizes that a wave-by-wave current-limiting condition is met, the controller is used for outputting a wave sending signal corresponding to the power conversion circuit, and the logic gate circuit is used for responding to the wave-by-wave current-limiting trigger signal, driving a main control switch tube in the power conversion circuit to be switched off and controlling the power conversion circuit to be switched off. According to the power conversion circuit, the follow current switch tube in the power conversion circuit is driven to operate based on the wave sending signal, so that when the power conversion circuit meets the wave-by-wave current limiting condition, the voltage difference on the energy storage inductor can be greatly reduced, the current falling speed on the energy storage inductor is further reduced, and the loading capacity of the power conversion circuit is greatly improved.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a protection circuit, a power converter, and a protection control method. Background Technology

[0002] Photovoltaic systems, energy storage systems, or integrated photovoltaic-energy storage systems typically include a power conversion circuit that converts direct current (DC) to alternating current (AC) to power the load. When starting a motor or other load, the current at the output port of the power conversion circuit will momentarily spike. To ensure proper motor startup, current limiting on a wave-by-wave basis is necessary.

[0003] Currently, in wave-by-wave current limiting schemes for power conversion circuits, the main control switch and freewheeling switch in the power conversion circuit are usually blocked. However, blocking the main control switch and freewheeling switch in the power conversion circuit will cause the current at the output port of the power conversion circuit to drop too quickly, even to zero, which will greatly affect the load-carrying capacity of the power conversion circuit. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a protection circuit, a power converter, and a protection control method to solve the problem in the prior art where the current at the output port of the power converter circuit decreases too quickly when current limiting is applied wave by wave, thus affecting the load-carrying capacity of the power converter circuit.

[0005] To achieve the above technical objectives, the embodiments of this application provide the following technical solutions:

[0006] Firstly, the embodiments described in this specification provide a protection circuit, including:

[0007] The sampling circuit is used to sample the current of the energy storage inductor in the connected power conversion circuit and output the sampling signal.

[0008] The first trigger circuit is used to output a wave-by-wave current limiting trigger signal when the sampled signal characterization satisfies the wave-by-wave current limiting condition;

[0009] The controller is used to output the transmission signal corresponding to the power conversion circuit;

[0010] A logic gate circuit is used to drive the main control switch in the power conversion circuit to turn off in response to the wave-by-wave current limiting trigger signal, and to drive the freewheeling switch in the power conversion circuit to operate based on the wave signal.

[0011] In one implementation, the controller is further configured to:

[0012] Count the cumulative number of times the wave-by-wave current limiting trigger signal is received within the current counting period;

[0013] When the cumulative number of times reaches a preset number, the blocking signal corresponding to the power conversion circuit is output;

[0014] The logic gate circuit is also used to control both the main control switch and the freewheeling switch to turn off in response to the blocking signal.

[0015] In one implementation, the controller is further configured to:

[0016] The wave signal is continuously output when the cumulative number of times has not reached the preset number of times.

[0017] In one embodiment, the first trigger circuit is specifically used for:

[0018] When the sampled signal indicates that the current limiting condition is met, the current limiting trigger signal is continuously output for a preset duration.

[0019] In one embodiment, the first trigger circuit is further configured to:

[0020] When the sampled signal does not meet the wave-by-wave current limiting condition and the current time is not within the preset duration, a first safety signal is output.

[0021] The logic gate circuit is also used to respond to the first safety signal and drive the main control switch and the freewheeling switch to operate based on the wave signal.

[0022] In one embodiment, the first trigger circuit includes a first comparison circuit and a timer, wherein the input terminal of the first comparison circuit serves as the input terminal of the first trigger circuit, and the output terminal of the timer serves as the output terminal of the first trigger circuit.

[0023] The first comparison circuit is used to output a comparison signal to the timer based on the comparison result between the sampled signal and the first threshold interval;

[0024] The timer is used to continuously output the wave-by-wave current limiting trigger signal for a preset duration when the comparison signal indicates that the sampled signal exceeds the first threshold interval, and to output the first safety signal when the comparison signal indicates that the sampled signal does not exceed the first threshold interval and the current time is not within the range of the preset duration.

[0025] In one embodiment, the comparison signal includes a first transition signal that transitions from a first level to a second level, and the timer responds to the first transition signal and continuously outputs the wave-by-wave current limiting trigger signal within the preset duration, wherein the first level signal indicates that the sampled signal has not exceeded the first threshold range, and the second level signal indicates that the sampled signal has exceeded the first threshold range.

[0026] The comparison signal also includes the first level or a second transition signal that transitions from the second level to the first level. When the timer is not within the range of the preset duration at the current time, it responds to the first level or the second transition signal and outputs the first security signal.

[0027] In one embodiment, the main control switch includes a first main control switch and a second main control switch, the freewheeling switch includes a target freewheeling switch, the target freewheeling switch and the first main control switch are complementaryly connected, the second main control switch is kept off, and the wave transmission signal includes sub-wave transmission signals corresponding to the first main control switch, the second main control switch and the target freewheeling switch respectively;

[0028] The logic gate circuit includes an adjustment circuit and a wave blocking control circuit; wherein...

[0029] The adjustment circuit is used to perform logical operations on each of the sub-wave signals, and output a first control signal to the blocking control circuit and a second control signal to the target freewheeling diode. The first control signal and the sub-wave signal corresponding to the second main control diode are not the same as the conduction control signal, and the first control signal and the second control signal are not the same as the conduction control signal.

[0030] The wave blocking control circuit is used to shield the first control signal and control the first main control tube to turn off when it receives the wave-by-wave current limiting trigger signal, and to output the first control signal to the first main control tube when it receives the first safety signal.

[0031] In one implementation, it further includes:

[0032] The second trigger circuit is used to output an overcurrent protection trigger signal when the sampled signal characterizes that the overcurrent protection condition is met.

[0033] The controller is also configured to respond to the overcurrent protection trigger signal by outputting a blocking signal corresponding to the power conversion circuit;

[0034] The logic gate circuit is also used to control both the main control switch and the freewheeling switch to turn off in response to the blocking signal.

[0035] In one embodiment, the second trigger circuit is further configured to:

[0036] When the sampled signal does not meet the overcurrent protection conditions, a second safety signal is output.

[0037] The controller is also configured to continuously output the wave signal in response to the second safety signal.

[0038] In one embodiment, the second trigger circuit includes a second comparator circuit and a one-way conduction circuit, wherein,

[0039] The first terminal of the unidirectional conduction circuit is connected to the output terminal of the second comparison circuit, and the second terminal of the unidirectional conduction circuit is used to input a preset voltage and serve as the output terminal of the second trigger circuit.

[0040] The second comparison circuit is used to output a reference voltage based on the comparison result between the sampled signal and the second threshold interval;

[0041] When the reference voltage is less than the preset voltage, the unidirectional conduction circuit is turned on, and the second trigger circuit outputs the overcurrent protection trigger signal;

[0042] When the reference voltage is greater than or equal to the preset voltage, the unidirectional conduction circuit is turned off, and the second trigger circuit outputs the second safety signal.

[0043] Secondly, embodiments of this specification provide a power converter, including a power conversion circuit and a protection circuit as described in any of the preceding claims.

[0044] Thirdly, embodiments of this specification provide a protection control method applied to a protection circuit as described in any of the foregoing claims, the method comprising:

[0045] Output the waveform signal corresponding to the power conversion circuit connected to the protection circuit to the logic gate circuit in the protection circuit;

[0046] The logic gate circuit is used to drive the main control switch in the power conversion circuit to turn off in response to the wave-by-wave current limiting signal output by the first trigger circuit in the protection circuit, and to drive the freewheeling switch in the power conversion circuit to operate based on the wave signal; the first trigger circuit is used to output the wave-by-wave current limiting trigger signal when the sampling signal output by the sampling circuit in the protection circuit indicates that the wave-by-wave current limiting condition is met, and the sampling circuit is used to sample the current of the energy storage inductor in the power conversion circuit and output the sampling signal.

[0047] Fourthly, embodiments of this specification provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the protection and control method described in any of the preceding claims.

[0048] Fifthly, embodiments of this specification provide a computer program product or computer program, the computer program product including a computer program stored in a computer-readable storage medium; the processor of the computer device reads the computer program from the computer-readable storage medium, and when the processor executes the computer program, it implements the protection control method as described in any of the preceding claims.

[0049] As can be seen from the above technical solutions, the embodiments of this application provide a protection circuit, a power converter, and a protection control method. The protection circuit includes a sampling circuit, a first trigger circuit, a controller, and a logic gate circuit. The sampling circuit is used to sample the current of the energy storage inductor in the connected power conversion circuit and output a sampling signal. The first trigger circuit is used to output a wave-by-wave current limiting trigger signal when the sampling signal indicates that the wave-by-wave current limiting condition is met. The controller is used to output a wave signal corresponding to the power conversion circuit. The logic gate circuit is used to drive the main control switch in the power conversion circuit to turn off in response to the wave-by-wave current limiting trigger signal, and to drive the freewheeling switch in the power conversion circuit to operate based on the wave signal. Thus, when the power conversion circuit meets the wave-by-wave current limiting condition, the freewheeling switch in the power conversion circuit can be guaranteed to operate normally, thereby ensuring that the current signal on the energy storage inductor is freewheeled through the freewheeling switch, which greatly reduces the voltage difference on the energy storage inductor, thereby reducing the rate of current decrease on the energy storage inductor and greatly improving the load-carrying capacity of the power conversion circuit.

[0050] Meanwhile, the solution in this application uses logic gate circuits to perform wave-by-wave current limiting control on the power conversion circuit, which can effectively reduce the complexity of the controller's software logic and improve the reliability of wave-by-wave current limiting control. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0052] Figure 1 This is a schematic diagram of the structure of a HERIC-type power conversion circuit in the prior art.

[0053] Figure 2This is a schematic diagram of the freewheeling loop for inductor current in an existing wave-by-wave current limiting scheme.

[0054] Figure 3 This is a schematic diagram of a protection circuit provided for implementation of this specification.

[0055] Figure 4 This is a schematic diagram of the freewheeling loop of the inductor current in the wave-by-wave current limiting scheme provided for the implementation of this specification.

[0056] Figure 5 This is a schematic diagram of a first trigger circuit provided for implementation of this specification.

[0057] Figure 6 This is a schematic diagram of a logic gate circuit provided for the implementation of this specification.

[0058] Figure 7 This is a schematic diagram of another protection circuit provided for the implementation of this specification.

[0059] Figure 8 This is a schematic diagram of a second trigger circuit provided for implementation of this specification.

[0060] Figure 9 This is a flowchart illustrating a protection control method provided for implementation of this specification. Detailed Implementation

[0061] Unless otherwise defined, the technical or scientific terms used in the embodiments of this specification shall have the ordinary meaning understood by one of ordinary skill in the art to which this specification pertains. The terms "first," "second," and similar terms used in the embodiments of this specification do not indicate any order, quantity, or importance, but are merely used to avoid confusion of constituent elements.

[0062] Unless the context otherwise requires, throughout this specification, "a plurality of" means "at least two," and "including" is interpreted as open-ended or encompassing, that is, "including, but not limited to." In the description of this specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this specification. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example.

[0063] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this specification.

[0064] As described in the background section, photovoltaic systems, energy storage systems, or integrated photovoltaic-energy storage systems typically include power conversion circuits, such as HERIC type power conversion circuits, T-type three-level power conversion circuits, I-type three-level power conversion circuits, NPC (Neutral Point Clamped) type power conversion circuits, ANPC (Advanced Neutral Point Clamped) type power conversion circuits, and split-phase power conversion circuits.

[0065] The power conversion circuit is used to convert direct current (DC) to alternating current (AC) to power the load. When starting a motor or other loads, the current at the output port of the power conversion circuit will typically spike momentarily. In order to ensure normal motor startup, current limiting on a wave-by-wave basis is required in the power conversion circuit.

[0066] Currently, in wave-by-wave current limiting schemes for power conversion circuits, the main control switch and freewheeling switch in the power conversion circuit are usually blocked. However, blocking the main control switch and freewheeling switch in the power conversion circuit will cause the inductor current to flow back to the bus, resulting in the current at the output port of the power conversion circuit dropping too quickly, or even dropping to zero, which greatly affects the load-carrying capacity of the power conversion circuit.

[0067] For example, taking a HERIC-type power conversion circuit as an example, such as Figure 1 As shown, the power conversion circuit includes an H-type inverter bridge composed of a first switch Q1, a second switch Q2, a third switch Q3, and a fourth switch Q4, and a freewheeling path composed of a fifth switch Q5 and a sixth switch Q6. The first switch Q1 and the second switch Q2 are connected to the positive input terminal V of the power conversion circuit. bus + connected, the third switch Q3 and the fourth switch Q4 are connected to the negative input terminal V of the power conversion circuit. bus - Connected to the positive input terminal V of the power conversion circuit bus + and negative input terminal V busA first capacitor C1 and a second capacitor C2 are connected in series between them; one end of the freewheeling path is connected to the connection point of the first switch Q1 and the third switch Q3, and the other end of the freewheeling path is connected to the connection point of the second switch Q2 and the fourth switch Q4; the connection point of the second switch Q2 and the fourth switch Q4 is also connected to the positive output terminal V of the power conversion circuit through the first energy storage inductor L1. out + connected, the connection point of the first switch Q1 and the third switch Q3 is also connected to the negative output terminal V of the power conversion circuit through the second energy storage inductor L2. out - Connected to the positive output terminal V of the power conversion circuit out + and negative output terminal V out A third capacitor C3 is provided between them. That is, each switch in the H-type inverter bridge can be called the main control switch, and each switch in the freewheeling path can be called the freewheeling switch.

[0068] During the normal operation of the HERIC power conversion circuit, in the positive half-cycle, the second switch Q2 and the third switch Q3 remain normally off, the sixth switch Q6 remains normally on, the first switch Q1 and the fourth switch Q4 are synchronously switched on and off at high frequency, and the fifth switch Q5 is complementary to the first switch Q1 and the fourth switch Q4 in switching on and off. In the negative half-cycle, the first switch Q1 and the fourth switch Q4 remain normally off, the fifth switch Q5 remains normally on, the second switch Q2 and the third switch Q3 are synchronously switched on and off at high frequency, and the sixth switch Q6 is complementary to the second switch Q2 and the third switch Q3 in switching on and off.

[0069] Taking the positive half-cycle as an example, after blocking both the main control switch and the freewheeling switch, the freewheeling circuit of the inductor current is as follows: Figure 2 As shown, it includes: first energy storage inductor L1 → third capacitor C3 → second energy storage inductor L2 → first switching transistor Q1 → positive input terminal V. bus +→ Negative input terminal V bus → Fourth switch Q4 → First energy storage inductor L1, therefore, the total voltage drop across the first energy storage inductor L1 and the second energy storage inductor L2 is -V bus -V out V bus V is the input voltage of the power conversion circuit. out As shown by the output voltage of the power conversion circuit, the voltage difference across the energy storage inductor increases dramatically, which causes the inductor currents on the first energy storage inductor L1 and the second energy storage inductor L2 to drop rapidly. In other words, this causes the current at the output port of the power conversion circuit to drop rapidly.

[0070] To address the problem of excessively rapid current drop at the output port of a power converter circuit, which affects its load-carrying capacity, when using traditional wave-by-wave current limiting methods, this application proposes a protection circuit, a power converter, and a protection control method. The protection circuit includes a sampling circuit, a first trigger circuit, a controller, and logic gate circuits. The sampling circuit samples the current of the energy storage inductor in the connected power converter circuit and outputs a sampling signal. The first trigger circuit outputs a wave-by-wave current limiting trigger signal when the sampling signal indicates that the wave-by-wave current limiting condition is met. The controller outputs the current limiting trigger signal for the power converter circuit. The corresponding waveform signal of the circuit, the logic gate circuit is used to respond to the wave-by-wave current limiting trigger signal, drive the main control switch in the power conversion circuit to turn off, and drive the freewheeling switch in the power conversion circuit to operate based on the waveform signal. Thus, when the power conversion circuit meets the wave-by-wave current limiting condition, the freewheeling switch in the power conversion circuit can be guaranteed to operate normally, thereby ensuring that the current signal on the energy storage inductor can be freewheeled through the freewheeling switch, which greatly reduces the voltage difference on the energy storage inductor, thereby reducing the rate of decrease of the current on the energy storage inductor and greatly improving the load-carrying capacity of the power conversion circuit.

[0071] Meanwhile, the solution in this application uses logic gate circuits to perform wave-by-wave current limiting control on the power conversion circuit, which can effectively reduce the complexity of the controller's software logic and improve the reliability of wave-by-wave current limiting control.

[0072] The following is combined with Figure 1 The application scenarios shown illustrate the exemplary protection circuit proposed in the embodiments of this application.

[0073] Reference Figure 3 This application first proposes a protection circuit, including:

[0074] The sampling circuit 101 is used to sample the current of the energy storage inductor in the connected power conversion circuit 102 and output a sampling signal.

[0075] The first trigger circuit 103 is used to output a wave-by-wave current limiting trigger signal when the sampled signal characterization satisfies the wave-by-wave current limiting condition;

[0076] Controller 104 is used to output the transmission signal corresponding to the power conversion circuit 102;

[0077] The logic gate circuit 105 is used to drive the main control switch in the power conversion circuit 102 to turn off in response to the wave-by-wave current limiting trigger signal, and to drive the freewheeling switch in the power conversion circuit 102 to operate based on the wave signal.

[0078] Specifically, the sampling circuit 101 can be connected to the power conversion circuit 102 to sample the current of the energy storage inductor in the power conversion circuit 102 and output a sampling signal. The power conversion circuit 102 can be a HERIC-type power conversion circuit, a T-type three-level power conversion circuit, an I-type three-level power conversion circuit, an NPC-type power conversion circuit, an ANPC-type power conversion circuit, or a split-phase power conversion circuit, etc., without specific limitations. For example, the sampling circuit 101 can perform differential sampling of the current in the energy storage inductor to obtain a voltage signal characterizing the current magnitude.

[0079] The input terminal of the first trigger circuit 103 is connected to the output terminal of the sampling circuit 101. It can determine whether the sampling signal output by the sampling circuit 101 indicates that the power conversion circuit 102 meets the wave-by-wave current limiting condition, and output a high-level or low-level wave-by-wave current limiting trigger signal when the wave-by-wave current limiting condition is met.

[0080] The controller 104 outputs a waveform signal corresponding to the power conversion circuit 102. This waveform signal can include sub-wave signals corresponding to each switch in the power conversion circuit 102. For any switch in the power conversion circuit 102, the corresponding sub-wave signal is used to control the switching on and off of that switch. It is understood that switches that are simultaneously turned on or off during normal operation of the power conversion circuit 102 can correspond to the same sub-wave signal. Specifically, for switches in the power conversion circuit 102 that require high-frequency switching during operation, their corresponding sub-wave signals can be PWM (Pulse Width Modulation) signals.

[0081] The logic gate circuit 105 is connected to the first trigger circuit 103, the controller 104, and the power conversion circuit 102 respectively. For example, when the logic gate circuit 105 receives the wave-by-wave current limiting trigger signal output by the first trigger circuit 103, it can drive the main control switch in the power conversion circuit 102 to turn off. At the same time, it can also determine the control signal corresponding to the freewheeling switch in the power conversion circuit 102 based on the sub-wave signals output by the controller 104, and drive the freewheeling switch to operate through the control signal. That is, the freewheeling switch in the power conversion circuit 102 is driven to operate normally according to the wave signal output by the controller 104.

[0082] Therefore, when the power conversion circuit 102 meets the wave-by-wave current limiting condition, by driving the freewheeling switch in the power conversion circuit 102 to operate normally, the current on the energy storage inductor can be guaranteed to freewheel through the freewheeling switch, which greatly reduces the voltage difference on the energy storage inductor, thereby reducing the rate of current decrease on the energy storage inductor and greatly improving the load-carrying capacity of the power conversion circuit 102. Figure 1Taking the HERIC power conversion circuit shown as an example, under the conditions of controlling the main control switch to block the waveform and controlling the freewheeling switch to operate normally, the freewheeling loop of the inductor current is as follows: Figure 4 As shown, the sequence is: first energy storage inductor L1 → third capacitor C3 → second energy storage inductor L2 → fifth switch Q5 → sixth switch Q6 → first energy storage inductor L1. At this point, the total voltage drop across the first energy storage inductor L1 and the second energy storage inductor L2 is -V. out The voltage difference is greatly reduced, which causes the inductor current on the first energy storage inductor L1 and the second energy storage inductor L2 to decrease slowly, greatly improving the load capacity of the power conversion circuit 102.

[0083] In addition, by using logic gate circuit 105 to perform wave-by-wave current limiting control on power conversion circuit 102, the complexity of software logic of controller 104 can be effectively reduced, and the reliability of wave-by-wave current limiting control can be improved.

[0084] In some embodiments, the controller 104 is further configured to:

[0085] Count the cumulative number of times the wave-by-wave current limiting trigger signal is received within the current counting period;

[0086] When the cumulative number of times reaches a preset number, the blocking signal corresponding to the power conversion circuit 102 is output;

[0087] The logic gate circuit 105 is also used to control both the main control switch and the freewheeling switch to turn off in response to the blocking signal.

[0088] Specifically, the controller 104 can also be connected to the output terminal of the first trigger circuit 103, thereby the controller 104 can count the received wave-by-wave current limiting trigger signals to count the cumulative number of wave-by-wave current limiting trigger signals received in the current counting period.

[0089] In practice, during the operation of the power conversion circuit 102, the controller 104 can count the number of current limiting triggers of the power conversion circuit 102 according to a preset counting period (e.g., 5 minutes). The current counting period is the counting period at the current moment.

[0090] If the controller 104 receives a preset number of wave-by-wave current limiting trigger signals within the current counting cycle, it outputs a blocking signal corresponding to the power conversion circuit 102. This blocking signal can include sub-blocking signals corresponding to each switch in the power conversion circuit 102. For any switch in the power conversion circuit 102, the corresponding sub-blocking signal is used to control the switch to turn off; for example, it can be a high-level signal. It is understood that switches that are simultaneously turned on or off during normal operation of the power conversion circuit 102 can correspond to the same sub-blocking signal.

[0091] When the logic gate circuit 105 receives the blocking signal output by the controller 104, regardless of whether it receives the wave-by-wave current limiting trigger signal at the current moment, it controls all the main control switches and freewheeling switches in the power conversion circuit 102 to turn off, so as to avoid the power conversion circuit 102 reaching the wave-by-wave current limiting trigger point multiple times in a short period of time, which would cause the switches to overheat and be damaged. This effectively improves the operational safety of the power conversion circuit 102.

[0092] It is understandable that after all the main control switches and freewheeling switches in the power conversion circuit 102 are turned off by the logic gate circuit 105, the power conversion circuit 102 can enter the standby state. At this time, the controller 104 can output a wave signal to the logic gate circuit 105 after receiving the start signal. The start signal can be manually input by the start button, or the start signal can be sent remotely by the remote control terminal. The start signal can also be output when the start condition is met according to the internal judgment logic.

[0093] In some embodiments, the controller 104 is further configured to:

[0094] The wave signal is continuously output when the cumulative number of times has not reached the preset number of times.

[0095] Specifically, the controller 104 can also continuously output the corresponding wave signal of the power conversion circuit 102 when the cumulative number of times the wave-by-wave current limiting trigger signal is received within the current counting cycle has not reached the preset number, so as to ensure the normal operation of the power conversion circuit 102.

[0096] In some embodiments, the first trigger circuit 103 is specifically used for:

[0097] When the sampled signal indicates that the current limiting condition is met, the current limiting trigger signal is continuously output for a preset duration.

[0098] Specifically, when the sampling signal characterization meets the wave-by-wave current limiting condition, the first trigger circuit 103 can also continuously output the wave-by-wave current limiting trigger signal for a preset duration, so that the logic gate circuit 105 can continuously block the main control switch in the power conversion circuit 102 for the preset duration, thereby ensuring that the output current of the power conversion circuit 102 is reduced to a range far away from the wave-by-wave current limiting trigger point. In this way, the frequent triggering of wave-by-wave current limiting can be effectively reduced, thereby ensuring the effective operation of the power conversion circuit 102.

[0099] The preset duration can be set according to actual needs. For example, the preset duration can be determined by experimental data to ensure that when the current limiting duration reaches the preset duration, the inductor current of the power conversion circuit 102 is in the inductor current threshold range corresponding to the current limiting trigger point, and the distance between the inductor current of the power conversion circuit 102 and the boundary value of the inductor current threshold range corresponding to the current limiting trigger point is greater than or equal to the preset distance.

[0100] In some embodiments, the first trigger circuit 103 is further configured to:

[0101] When the sampled signal does not meet the wave-by-wave current limiting condition and the current time is not within the preset duration, a first safety signal is output.

[0102] The logic gate circuit 105 is also used to respond to the first safety signal and drive the main control switch and the freewheeling switch to operate based on the wave signal.

[0103] Specifically, the first trigger circuit 103 is also used to output a first safety signal when the sampled signal does not meet the wave-by-wave current limiting condition and the current time is not within the preset duration of continuously outputting the wave-by-wave current limiting trigger signal. The first safety signal is opposite in direction to the wave-by-wave current limiting trigger signal, for example, one is high level and the other is low level.

[0104] It is understandable that during the process of the first trigger circuit 103 continuously outputting the wave-by-wave current limiting trigger signal within a preset duration, if the received sampled signal indicates that the wave-by-wave current limiting condition is not met, the wave-by-wave current limiting trigger signal will still be output. When the duration of outputting the wave-by-wave current limiting trigger signal reaches the preset duration, the first trigger circuit 103 will determine whether to output the first safety signal or the wave-by-wave current limiting trigger signal based on the received sampled signal. For example, when the duration of outputting the wave-by-wave current limiting trigger signal reaches the preset duration, if the received sampled signal indicates that the wave-by-wave current limiting condition is not met, the first trigger circuit 103 will output the first safety signal. If the received sampled signal indicates that the wave-by-wave current limiting condition is still met, the first trigger circuit 103 will continue to output the wave-by-wave current limiting trigger signal until the received sampled signal indicates that the wave-by-wave current limiting condition is not met, at which point the first safety signal will be output.

[0105] The logic gate circuit 105 is also used to respond to the first safety signal and drive the main control switch and the freewheeling switch to operate based on the wave signal output by the controller 104, that is, to control the power conversion circuit 102 to operate normally, thereby ensuring the safe and reliable operation of the power conversion circuit 102.

[0106] In some embodiments, the first trigger circuit 103 includes a first comparison circuit and a timer, wherein the input terminal of the first comparison circuit serves as the input terminal of the first trigger circuit 103, and the output terminal of the timer serves as the output terminal of the first trigger circuit 103.

[0107] The first comparison circuit is used to output a comparison signal to the timer based on the comparison result between the sampled signal and the first threshold interval;

[0108] The timer is used to continuously output the wave-by-wave current limiting trigger signal for a preset duration when the comparison signal indicates that the sampled signal exceeds the first threshold interval, and to output the first safety signal when the comparison signal indicates that the sampled signal does not exceed the first threshold interval and the current time is not within the range of the preset duration.

[0109] Specifically, the input terminal of the first comparison circuit can be used as the input terminal of the first trigger circuit 103 and connected to the output terminal of the sampling circuit 101 to receive the sampling signal output by the sampling circuit 101.

[0110] The first comparison circuit can output a comparison signal based on the comparison result between the sampled signal and the first threshold interval. The first threshold interval can be the inductor current threshold interval corresponding to the wave-by-wave current limiting trigger point. The first comparison circuit can be a window comparison circuit.

[0111] The comparison signal can be either low or high, depending on the structure of the first comparison circuit. For example, when the sampled signal is within the first threshold range, it indicates that the wave-by-wave current limiting condition is not met, and the first comparison circuit can output a high-level comparison signal. When the sampled signal exceeds the first threshold range, it indicates that the wave-by-wave current limiting condition is met, and the first comparison circuit can output a low-level comparison signal.

[0112] The input terminal of the timer can be connected to the output terminal of the first comparator circuit to receive the comparison signal output by the first comparator circuit. At the same time, the output terminal of the timer can be connected to the logic gate circuit 105 and the controller 104. That is, the output terminal of the timer can be used as the output terminal of the first trigger circuit 103.

[0113] In implementation, when the comparison signal indicates that the sampled signal exceeds the first threshold interval, it indicates that the wave-by-wave current limiting condition is met. At this time, the timer can use the comparison signal indicating that the sampled signal exceeds the first threshold interval as the wave-by-wave current limiting trigger signal and continuously output the wave-by-wave current limiting trigger signal for a preset duration. Conversely, when the comparison signal indicates that the sampled signal does not exceed the first threshold interval, it indicates that the wave-by-wave current limiting condition is not met. In this case, if the current time is within the preset duration of continuously outputting the wave-by-wave current limiting trigger signal, the timer can block the comparison signal indicating that the sampled signal does not exceed the first threshold interval and continuously output the wave-by-wave current limiting trigger signal. If the current time is not within the preset duration of continuously outputting the wave-by-wave current limiting trigger signal, the timer can use the comparison signal indicating that the sampled signal does not exceed the first threshold interval as the first safety signal and output the first safety signal. The circuit structure is simple and can effectively trigger wave-by-wave current limiting.

[0114] It is understandable that when the comparison signal represents the sampled signal not exceeding the first threshold range, the timer does not trigger a delay. Therefore, when the wave-by-wave current limiting condition is met, the power conversion circuit 102 can be controlled for wave-by-wave current limiting as soon as possible to ensure the safe and reliable operation of the power conversion circuit 102.

[0115] Optionally, the structure of the first trigger circuit 103 can be as follows: Figure 5 As shown, the first comparison circuit includes a first comparator U1 and a second comparator U2. The non-inverting input of the first comparator U1 is connected to a first voltage divider circuit, used to input the upper limit value of the first threshold range. The first voltage divider circuit includes a first resistor R1 and a second resistor R2 connected in sequence. The first resistor R1 is connected to a 3V reference voltage source, and the second resistor R2 is grounded. The non-inverting input of the first comparator U1 is connected to the junction of the first resistor R1 and the second resistor R2. The inverting input of the first comparator U1 is connected to the output of the sampling circuit 101 through a third resistor R3, used to input the sampling signal IL_INV. The non-inverting input of the second comparator U2 is connected to the output of the sampling circuit 101 through the fourth resistor R4, and is used to input the sampling signal IL_INV; the inverting input of the second comparator U2 is connected to the second voltage divider circuit, and is used to input the lower limit value of the first threshold interval. The second voltage divider circuit includes a fifth resistor R5 and a sixth resistor R6 connected in sequence. The fifth resistor R5 is connected to a 3V reference voltage source, and the sixth resistor R6 is grounded. The inverting input of the second comparator U2 is connected to the connection point of the fifth resistor R5 and the sixth resistor R6.

[0116] The outputs of the first comparator U1 and the second comparator U2 are connected to a 3.3V reference voltage source via a seventh resistor R7. The outputs of the first comparator U1 and the second comparator U2 are also connected to the input of the timer TM via a first filter circuit. The first filter circuit includes an eighth resistor R8 and a fourth capacitor C4. One end of the eighth resistor R8 is connected to the output of the first comparator U1 and the second comparator U2, and the other end is connected to the input of the timer TM. One end of the fourth capacitor C4 is connected to the junction of the eighth resistor R8 and the timer TM, and the other end is grounded. The output of the timer TM outputs either a wave-by-wave current-limiting trigger signal TRI1 or a first safety signal SAFE1 via a second filter circuit. The second filter circuit includes a ninth resistor R9 and a fifth capacitor C5. The first end of the ninth resistor R9 is connected to the output of the timer TM, and the second end of the ninth resistor R9 serves as the output of the first trigger circuit 103. One end of the fifth capacitor C5 is connected to the second end of the ninth resistor R9, and the other end is grounded. Additionally, the power supply terminal of the timer TM is used to input a 5V supply voltage, and the ground terminal of the timer TM is grounded. Among them, the timer TM can be a 555 timer.

[0117] When the sampled signal is within the first threshold range, both the first comparator U1 and the second comparator U2 output a high level, the comparison signal POE_CBC output by the output terminal of the first comparator circuit is a high level, and when the timer TM is not within the preset duration range at the current time, it outputs a high-level first safety signal.

[0118] When the sampled signal is greater than the upper limit of the first threshold interval, the first comparator U1 outputs a low level, the second comparator U2 outputs a high level, the comparison signal POE_CBC output by the output terminal of the first comparator circuit is low, the output signal of the timer TM is reversed, and a low-level wave-by-wave current limiting trigger signal is continuously output within a preset duration.

[0119] When the sampled signal is less than the lower limit of the first threshold interval, the first comparator U1 outputs a high level, the second comparator U2 outputs a low level, the comparison signal POE_CBC output by the output terminal of the first comparator circuit is low, the output signal of the timer TM is reversed, and a low-level wave-by-wave current limiting trigger signal is continuously output within a preset duration.

[0120] In some embodiments, the comparison signal includes a first transition signal that transitions from a first level to a second level, and the timer responds to the first transition signal and continuously outputs the wave-by-wave current limiting trigger signal for a preset duration. The first level signal indicates that the sampled signal has not exceeded the first threshold range, and the second level signal indicates that the sampled signal has exceeded the first threshold range.

[0121] The comparison signal also includes the first level or a second transition signal that transitions from the second level to the first level. When the timer is not within the range of the preset duration at the current time, it responds to the first level or the second transition signal and outputs the first security signal.

[0122] Specifically, the comparison signal may include a first transition signal that transitions from a first level to a second level. The first level represents the comparison signal output by the first comparison circuit when the sampled signal does not exceed a first threshold range, and the second level represents the comparison signal output by the first comparison circuit when the sampled signal exceeds the first threshold range. That is, the first and second levels are in opposite directions, and one level can be high and the other low.

[0123] Specifically, when the comparison signal transitions from the first level to the second level, it indicates that the inductor current of the power conversion circuit 102 has reached the wave-by-wave current limiting trigger point. The timer responds to this first transition signal, using the second level as the wave-by-wave current limiting trigger signal, and continuously outputs this signal for a preset duration. That is, when the first level is high and the second level is low, the timer can be triggered by the falling edge; when the first level is low and the second level is high, the timer can be triggered by the rising edge. This allows the logic gate circuit 105 to block the main control switch in the power conversion circuit 102 at the instant the inductor current of the power conversion circuit 102 reaches the wave-by-wave current limiting trigger point, effectively improving the response speed of the wave-by-wave current limiting and ensuring the safe and effective operation of the power conversion circuit 102.

[0124] It is understandable that within the preset duration of the timer continuously outputting the wave-by-wave current limiting trigger signal, the timer can shield the received comparison signal until the preset duration ends.

[0125] In addition, the comparison signal may also include a second transition signal that transitions from the second level to the first level. When the comparison signal transitions from the second level to the first level, it can characterize the instant when the inductor current of the power conversion circuit 102 returns to normal.

[0126] If the current time is not within the preset duration of the timer's continuous output of the wave-by-wave current limiting trigger signal, then when the comparison signal changes from the second level to the first level, or when the comparison signal is at the first level, the timer can use the first level as the first safety signal and output it, thereby ensuring the effective operation of the power conversion circuit 102.

[0127] It is understandable that if the comparison signal is still at the second level when the timer continuously outputs the wave-by-wave current limiting trigger signal for a preset duration, the timer delay will not be triggered. At this time, the timer can use the second level as the wave-by-wave current limiting trigger signal and output it. When the second transition signal is received, the first level is used as the first safety signal and output it, thereby ensuring the effective operation of the power conversion circuit 102.

[0128] In some embodiments, the main control switch includes a first main control switch and a second main control switch, the freewheeling switch includes a target freewheeling switch, the target freewheeling switch and the first main control switch are complementaryly connected, the second main control switch is kept off, and the transmitting signal includes sub-transmitting signals corresponding to the first main control switch, the second main control switch and the target freewheeling switch respectively;

[0129] The logic gate circuit 105 includes an adjustment circuit and a wave blocking control circuit; wherein...

[0130] The adjustment circuit is used to perform logical operations on each of the sub-wave signals, and output a first control signal to the blocking control circuit and a second control signal to the target freewheeling diode. The first control signal and the sub-wave signal corresponding to the second main control diode are not the same as the conduction control signal, and the first control signal and the second control signal are not the same as the conduction control signal.

[0131] The wave blocking control circuit is used to shield the first control signal and control the first main control tube to turn off when it receives the wave-by-wave current limiting trigger signal, and to output the first control signal to the first main control tube when it receives the first safety signal.

[0132] Specifically, the main control switch can include a first main control switch and a second main control switch. The first main control switch can be a switch that needs to maintain high-frequency switching during normal operation of the power conversion circuit 102, and the second main control switch can be a switch that needs to remain in the off state during normal operation of the power conversion circuit 102. Meanwhile, the target freewheeling switch in the freewheeling switch can be a switch that needs to complement the first main control switch during normal operation of the power conversion circuit 102. For example, with... Figure 1 Taking the HERIC power conversion circuit shown as an example, during the positive half-cycle, the first main control transistor can be the first switch Q1 and the fourth switch Q4, the second main control transistor can be the second switch Q2 and the third switch Q3, and the target freewheeling transistor can be the fifth switch Q5; during the negative half-cycle, the first main control transistor can be the second switch Q2 and the third switch Q3, the second main control transistor can be the first switch Q1 and the fourth switch Q4, and the target freewheeling transistor can be the sixth switch Q6.

[0133] The waveform signal output by the controller 104 may include the sub-wave signal corresponding to the first main control tube, the sub-wave signal corresponding to the second main control tube, the sub-wave signal corresponding to the target freewheeling tube, and the sub-wave signals corresponding to other switching tubes other than the target freewheeling tube in the freewheeling switching tubes.

[0134] The logic gate circuit 105 may include an adjustment circuit and a blocking control circuit. The input terminal of the adjustment circuit can be connected to the controller 104 to receive the wave transmission signal or blocking signal output by the controller 104. The first output terminal of the adjustment circuit can be connected to the blocking control circuit to output a first control signal corresponding to the first main control transistor to the blocking control circuit. The second output terminal of the adjustment circuit can be connected to the target freewheeling transistor to output a second control signal corresponding to the target freewheeling transistor to the target freewheeling transistor. The first input terminal of the blocking control circuit is connected to the first output terminal of the adjustment circuit. The second input terminal of the blocking control circuit is connected to the output terminal of the first trigger circuit 103 to receive the wave-by-wave current limiting trigger signal or the first safety signal output by the first trigger circuit 103. The output terminal of the blocking control circuit is connected to the first main control transistor to control the on / off state of the first main control transistor. Furthermore, the logic gate circuit 105 can also send the sub-wave transmission signal corresponding to the second main control transistor as a third control signal to the second main control transistor, and send the sub-wave transmission signals corresponding to other switches in the freewheeling transistor as fourth control signals to those other switches.

[0135] The adjustment circuit performs logical operations on the sub-wavelength signals corresponding to the first main control transistor, the second main control transistor, and the target freewheeling transistor to output a first control signal to the blocking control circuit and a second control signal to the target freewheeling transistor. The first control signal and the sub-wavelength signal corresponding to the second main control transistor are not simultaneously acting as conduction control signals, thus preventing the first and second main control transistors from conducting simultaneously. For example, when both the sub-wavelength signals corresponding to the second and first main control transistors are acting as conduction control signals, the first control signal output by the adjustment circuit after logical operations can be a turn-off control signal to prevent the first and second main control transistors from conducting simultaneously, thereby effectively ensuring the safe and efficient operation of the power conversion circuit 102.

[0136] Furthermore, the first control signal and the second control signal are not simultaneously turn-on control signals, so as to control the first main control transistor and the target freewheeling transistor to not be turned on at the same time. For example, when the sub-wavelength signal corresponding to the first main control transistor and the sub-wavelength signal corresponding to the target freewheeling transistor are both turn-on control signals, and the sub-wavelength signal corresponding to the second main control transistor is a turn-off control signal, the first control signal and the second control signal output by the adjustment circuit after logical operation can both be turn-off control signals, so as to avoid the first main control transistor and the target freewheeling transistor being turned on at the same time; when the sub-wavelength signal corresponding to the first main control transistor, the sub-wavelength signal corresponding to the second main control transistor, and the sub-wavelength signal corresponding to the target freewheeling transistor are all turn-on control signals, the first control signal output by the adjustment circuit after logical operation can be a turn-off control signal, and the second control signal output can be a turn-on control signal, so as to avoid the first main control transistor and the second main control transistor being turned on at the same time, and also to avoid the first main control transistor and the target freewheeling transistor being turned on at the same time, thereby effectively ensuring the safe and efficient operation of the power conversion circuit 102.

[0137] When the wave-by-wave current limiting signal output by the first trigger circuit 103 is received, the wave-by-wave current limiting circuit can shield the first control signal output by the adjustment circuit and output a shutdown control signal to the first main control transistor to control the first main control transistor to turn off and limit the current of the power conversion circuit 102 wave by wave. In addition, when the wave-by-wave current limiting circuit receives the first safety signal output by the first trigger circuit 103, the wave-by-wave current limiting circuit can output the first control signal output by the adjustment circuit to the first main control transistor to ensure the normal operation of the power conversion circuit 102.

[0138] Optionally, taking the turn-off control signal as high level, the turn-on control signal as low level, the wave-by-wave current limiting trigger signal as low level, and the first safety signal as high level as an example, the structure of logic gate circuit 105 can be as follows: Figure 6As shown. The adjustment circuit includes a first NOT gate N1, a second NOT gate N2, a third NOT gate N3, a first AND gate AND1, a second AND gate AND2, and a first NAND gate NAND1. The first input terminal of the first AND gate AND1 is connected to the first NOT gate N1, and the input terminal of the first AND gate is connected to the controller 104, used to input the sub-wave signal EPWM_1A corresponding to the first main control transistor. The second input terminal of the first AND gate AND1 is connected to the controller 104, used to input the sub-wave signal EPWM_2A corresponding to the second main control transistor. The output terminal of the first AND gate AND1 is connected to the first input terminal of the second AND gate AND2, and the second input terminal of the second AND gate AND2 is connected to the controller 104, used to input the sub-wave signal EPWM_1B corresponding to the target freewheeling transistor. The output terminal of the second AND gate AND2 serves as the first output terminal of the adjustment circuit and is connected to the first input terminal of the wave blocking control circuit. The input terminal of the second NOT gate N2 is connected to the controller 104 and is used to input the sub-wave signal EPWM_1B corresponding to the target freewheeling diode. The output terminal of the second NOT gate N2 is connected to the first input terminal of the first NAND gate NAND1. The input terminal of the third NOT gate N3 is connected to the output terminal of the first AND gate AND1, and the output terminal of the third NOT gate N3 is connected to the second input terminal of the first NAND gate NAND1. The output terminal of the first NAND gate NAND1 is connected to the target freewheeling diode as the second output terminal of the adjustment circuit.

[0139] Considering the simplicity of the wave blocking control circuit, Figure 6 The signal output from the first output terminal of the adjustment circuit is a signal opposite in direction to the first control signal, and the signal output from the first output terminal of the adjustment circuit is inverted in the wave-blocking control circuit. The wave-blocking control circuit includes a second NAND gate NAND2. The first input terminal of the second NAND gate NAND2 is connected to the output terminal of the second AND gate NAND2, and the second input terminal of the second NAND gate NAND2 is connected to the output terminal of the first trigger circuit 103, used to input the wave-by-wave current-limiting trigger signal TRI1 or the first safety signal SAFE1. The output terminal of the second NAND gate NAND2 serves as the output terminal of the wave-blocking control circuit and is connected to the first main control transistor. Therefore, when the first trigger circuit 103 outputs a high-level first safety signal, the second NAND gate NAND2 inverts the signal output from the first output terminal of the adjustment circuit and outputs it as the first control signal to the first main control transistor to control its operation. When the first trigger circuit 103 outputs a low-level wave-by-wave current-limiting trigger signal, regardless of whether the first output terminal of the adjustment circuit outputs a high level or a low level, the second NAND gate NAND2 outputs a high-level turn-off control signal to the first main control transistor, thereby achieving wave blocking for the first main control transistor. It can be understood that the second main control transistor remains in the off state during the normal operation of the power conversion circuit 102. Therefore, wave blocking control of the main control switching transistor can be achieved by only blocking the first main control transistor.

[0140] It should be noted that, Figure 6 The document does not show the portion where the sub-wave emission signal corresponding to the second main control transistor is sent to the second main control transistor as the third control signal, nor the portion where the sub-wave emission signal corresponding to the other switch in the freewheeling switch is sent to the other switch as the fourth control signal. Additionally, two sets of logic gate circuits 105 can be configured, one for operation during the positive half-cycle and the other for operation during the negative half-cycle.

[0141] Specifically, when the first trigger circuit 103 outputs a high-level first safety signal... Figure 6 The first and second control signals output by the logic gate circuit 105 under different waveform signals are shown in Table 1:

[0142] Table 1

[0143] EPWM_2A EPWM_1A EPWM_1B First control signal Second control signal 0 0 0 1 0 0 0 1 1 1 0 1 0 1 0 0 1 1 1 1 1 0 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1 1 1

[0144] As shown in Table 1, the first control signal and the second control signal are not both low-level conduction control signals at the same time. At the same time, the first control signal and the sub-wave signal corresponding to the second main control tube are not both low-level conduction control signals at the same time, thereby ensuring the safe and reliable operation of the power conversion circuit 102.

[0145] In some embodiments, such as Figure 7 As shown, it also includes:

[0146] The second trigger circuit 106 is used to output an overcurrent protection trigger signal when the sampled signal characterizes that the overcurrent protection condition is met.

[0147] The controller 104 is also configured to output a blocking signal corresponding to the power conversion circuit 102 in response to the overcurrent protection trigger signal;

[0148] The logic gate circuit 105 is also used to control both the main control switch and the freewheeling switch to turn off in response to the blocking signal.

[0149] Specifically, the protection circuit also includes a second trigger circuit 106. The input terminal of the second trigger circuit 106 is connected to the output terminal of the sampling circuit 101. It can determine whether the sampling signal output by the sampling circuit 101 indicates that the power conversion circuit 102 meets the overcurrent protection conditions, and output a high-level or low-level overcurrent protection trigger signal when the overcurrent protection conditions are met. It can be understood that the overcurrent protection trigger point can be higher than the wave-by-wave current limiting trigger point. That is, during the operation of the power conversion circuit 102, when the motor is started and the load is equal, wave-by-wave current limiting will be triggered first. However, if the current rises too quickly, there is also a possibility of directly triggering the overcurrent protection.

[0150] The controller 104 can also be connected to the output of the second trigger circuit 106. When the controller 104 receives the overcurrent protection trigger signal output by the second trigger circuit 106, it can output the blocking signal corresponding to each switch in the power conversion circuit 102. For example, the blocking signal can be a high level. When the logic gate circuit 105 receives the blocking signal, it can output the turn-off control signal corresponding to each main control switch and freewheeling switch in the power conversion circuit 102, so as to control the main control switch and freewheeling switch in the power conversion circuit 102 to be turned off.

[0151] by Figure 6 Taking the logic gate circuit 105 as an example, when EPWM_2A, EPWM_1A, and EPWM_1B are all high-level turn-off control signals, the second control signal is a turn-off signal, and the second AND gate AND2 outputs a low level. At this time, regardless of whether the first trigger circuit 103 outputs a high-level first safety signal or a low-level wave-by-wave current limiting trigger signal, the second NAND gate NAND2 outputs a high-level turn-off control signal to the first main control transistor, thereby effectively controlling the main control switch and the freewheeling switch in the power conversion circuit 102 to be turned off.

[0152] It is understandable that after all the main control switches and freewheeling switches in the power conversion circuit 102 are turned off by the logic gate circuit 105, the power conversion circuit 102 can enter the standby state. At this time, the controller 104 can output a wave signal to the logic gate circuit 105 after receiving the start signal. The start signal can be manually input by the start button, or the start signal can be sent remotely by the remote control terminal. The start signal can also be output when the start condition is met according to the internal judgment logic.

[0153] In some embodiments, the second trigger circuit 106 is further configured to:

[0154] When the sampled signal does not meet the overcurrent protection conditions, a second safety signal is output.

[0155] The controller 104 is also configured to continuously output the wave signal in response to the second safety signal.

[0156] Specifically, the second trigger circuit 106 is also used to output a second safety signal when the sampling signal characterization does not meet the overcurrent protection conditions. The second safety signal is opposite in direction to the overcurrent protection trigger signal, for example, one is high level and the other is low level.

[0157] The controller 104 can also continuously output the corresponding waveform signal of the power conversion circuit 102 when it receives the second safety signal output by the second trigger circuit 106, so as to ensure the normal operation of the power conversion circuit 102.

[0158] In some embodiments, the second trigger circuit 106 includes a second comparison circuit and a one-way conduction circuit, wherein,

[0159] The first terminal of the unidirectional conduction circuit is connected to the output terminal of the second comparison circuit, and the second terminal of the unidirectional conduction circuit is used to input a preset voltage and serve as the output terminal of the second trigger circuit 106.

[0160] The second comparison circuit is used to output a reference voltage based on the comparison result between the sampled signal and the second threshold interval;

[0161] When the reference voltage is less than the preset voltage, the unidirectional conduction circuit is turned on, and the second trigger circuit 106 outputs the overcurrent protection trigger signal;

[0162] When the reference voltage is greater than or equal to the preset voltage, the unidirectional conduction circuit is turned off, and the second trigger circuit 106 outputs the second safety signal.

[0163] Specifically, the second trigger circuit 106 may include a second comparison circuit and a unidirectional conduction circuit. The input terminal of the second comparison circuit serves as the input terminal of the second trigger circuit 106 and is connected to the output terminal of the sampling circuit 101 to receive the sampling signal output by the sampling circuit 101.

[0164] The second comparison circuit can output a reference voltage based on the comparison result between the sampled signal and the second threshold interval. The second comparison circuit can be a window comparison circuit. The second threshold interval can be the inductor current threshold interval corresponding to the overcurrent protection trigger point. The upper limit of the second threshold interval can be greater than the upper limit of the first threshold interval, while the lower limit of the second threshold interval can be lower than the lower limit of the first threshold interval. That is, the second threshold interval can include the first threshold interval. This allows for the first triggering of wave-by-wave current limiting when the current at the output port of the power conversion circuit 102 increases due to a load on the starting motor, thus ensuring normal starting of the motor under load.

[0165] The reference voltage can be either a low-level or high-level reference voltage, which can be determined based on the structure of the second comparator circuit. For example, when the sampled signal is within the second threshold range, it indicates that the overcurrent protection condition is not met, and the second comparator circuit can output a high-level reference voltage. When the sampled signal exceeds the second threshold range, it indicates that the overcurrent protection condition is met, and the second comparator circuit can output a low-level reference voltage.

[0166] The first terminal of the unidirectional conduction circuit is connected to the output terminal of the second comparator circuit, and the second terminal of the unidirectional conduction circuit is used to input a preset voltage and serves as the output terminal of the second trigger circuit 106. Optionally, the unidirectional conduction circuit can be a diode, with the first terminal of the diode being the cathode and the second terminal being the anode.

[0167] Specifically, when the reference voltage is less than the preset voltage, the unidirectional conduction circuit is turned on, and the second trigger circuit 106 outputs a low-level overcurrent protection trigger signal. When the reference voltage is greater than or equal to the preset voltage, the unidirectional conduction circuit is turned off, and the second trigger circuit 106 outputs a high-level second safety signal. Thus, the overcurrent protection can be triggered accurately and reliably through the second trigger circuit 106.

[0168] Optionally, the structure of the second trigger circuit 106 can be as follows: Figure 8 As shown, the second comparison circuit includes a third comparator U3 and a fourth comparator U4. The non-inverting input of the third comparator U3 is connected to a third voltage divider circuit, used to input the upper limit value of the second threshold range. The third voltage divider circuit includes a tenth resistor R connected in sequence. 10 and the eleventh resistor R 11 The tenth resistor R 10 Connected to a 3V reference voltage source, the eleventh resistor R 11 Grounded, the non-inverting input of the third comparator U3 is connected to the tenth resistor R. 10 and the eleventh resistor R 11 The connection points are connected; the inverting input of the third comparator U3 is connected through the twelfth resistor R. 12 It is connected to the output of sampling circuit 101 and used to input the sampling signal IL_INV. The non-inverting input of the fourth comparator U4 is connected to the thirteenth resistor R. 13 The sampling circuit 101 is connected to its output terminal for inputting the sampling signal IL_INV; the inverting input terminal of the fourth comparator U4 is connected to the fourth voltage divider circuit for inputting the lower limit value of the second threshold interval. The fourth voltage divider circuit includes a fourteenth resistor R connected in sequence. 14 and the fifteenth resistor R 15 The fourteenth resistor R 14 Connected to a 3V reference voltage source, the fifteenth resistor R 15 Grounded, the inverting input of the fourth comparator U4 is connected to the fourteenth resistor R. 14 and the fifteenth resistor R 15 The connection points are connected.

[0169] The outputs of the third comparator U3 and the fourth comparator U4 are connected to the sixteenth resistor R. 16 Connected to a 3.3V reference voltage source, the outputs of the third comparator U3 and the fourth comparator U4 are also connected to the seventeenth resistor R. 17The cathode of diode D is connected to the anode of diode D, and the anode of diode D is connected to the eighteenth resistor R. 18 Connected to a 3.3V reference voltage source, the anode of diode D is connected to the eighteenth resistor R. 18 The connection point is through the nineteenth resistor R 19 Output overcurrent protection trigger signal TRI2 or second safety signal SAFE2.

[0170] When the sampled signal is within the second threshold range, both the third comparator U3 and the fourth comparator U4 output a high level, and the output of the second comparator circuit (the seventeenth resistor R)... 17 The connection point with the cathode of diode D outputs a high-level reference voltage, diode D is cut off, and the second trigger circuit 106 outputs a high-level second safety signal.

[0171] When the sampled signal is greater than the upper limit of the second threshold interval, the third comparator U3 outputs a low level, the fourth comparator U4 outputs a high level, the output terminal of the second comparator circuit outputs a low-level reference voltage, the diode D is turned on, and the second trigger circuit 106 outputs a low-level overcurrent protection trigger signal.

[0172] When the sampled signal is less than the lower limit of the second threshold interval, the third comparator U3 outputs a high level, the fourth comparator U4 outputs a low level, the output terminal of the second comparator circuit outputs a low-level reference voltage, the diode D is turned on, and the second trigger circuit 106 outputs a low-level overcurrent protection trigger signal.

[0173] Corresponding to the protection circuit described above, this application also provides a power converter, including a power conversion circuit 102 and a protection circuit as described in any of the above embodiments.

[0174] In another embodiment of this application, a protection control method is also provided, applied to a protection circuit as described in any of the above embodiments, such as... Figure 9 As shown, the method includes:

[0175] S901. Output the waveform signal corresponding to the power conversion circuit 102 connected to the protection circuit to the logic gate circuit 105 in the protection circuit;

[0176] The logic gate circuit 105 is used to drive the main control switch in the power conversion circuit 102 to turn off in response to the wave-by-wave current limiting signal output by the first trigger circuit 103 in the protection circuit, and to drive the freewheeling switch in the power conversion circuit 102 to operate based on the wave signal; the first trigger circuit 103 is used to output the wave-by-wave current limiting trigger signal when the sampling signal output by the sampling circuit 101 in the protection circuit indicates that the wave-by-wave current limiting condition is met; the sampling circuit 101 is used to sample the current of the energy storage inductor in the power conversion circuit 102 and output the sampling signal.

[0177] In some embodiments, it also includes:

[0178] Count the cumulative number of times the wave-by-wave current limiting trigger signal is received within the current counting period;

[0179] When the cumulative number of times reaches a preset number, the blocking signal corresponding to the power conversion circuit 102 is output to the logic gate circuit 105. The logic gate circuit 105 is also used to control the main control switch and the freewheeling switch to be turned off in response to the blocking signal.

[0180] In some embodiments, it also includes:

[0181] The wave signal is continuously output when the cumulative number of times has not reached the preset number of times.

[0182] In some embodiments, the first trigger circuit 103 is specifically used for:

[0183] When the sampled signal indicates that the current limiting condition is met, the current limiting trigger signal is continuously output for a preset duration.

[0184] In some embodiments, the first trigger circuit 103 is further configured to:

[0185] When the sampled signal does not meet the wave-by-wave current limiting condition and the current time is not within the preset duration, a first safety signal is output.

[0186] The logic gate circuit 105 is also used to respond to the first safety signal and drive the main control switch and the freewheeling switch to operate based on the wave signal.

[0187] In some embodiments, the first trigger circuit 103 includes a first comparison circuit and a timer, wherein the input terminal of the first comparison circuit serves as the input terminal of the first trigger circuit 103, and the output terminal of the timer serves as the output terminal of the first trigger circuit 103.

[0188] The first comparison circuit is used to output a comparison signal to the timer based on the comparison result between the sampled signal and the first threshold interval;

[0189] The timer is used to continuously output the wave-by-wave current limiting trigger signal for a preset duration when the comparison signal indicates that the sampled signal exceeds the first threshold interval, and to output the first safety signal when the comparison signal indicates that the sampled signal does not exceed the first threshold interval and the current time is not within the range of the preset duration.

[0190] In some embodiments, the comparison signal includes a first transition signal that transitions from a first level to a second level, and the timer responds to the first transition signal and continuously outputs the wave-by-wave current limiting trigger signal for a preset duration. The first level signal indicates that the sampled signal has not exceeded the first threshold range, and the second level signal indicates that the sampled signal has exceeded the first threshold range.

[0191] The comparison signal also includes the first level or a second transition signal that transitions from the second level to the first level. When the timer is not within the range of the preset duration at the current time, it responds to the first level or the second transition signal and outputs the first security signal.

[0192] In some embodiments, the main control switch includes a first main control switch and a second main control switch, the freewheeling switch includes a target freewheeling switch, the target freewheeling switch and the first main control switch are complementaryly connected, the second main control switch is kept off, and the transmitting signal includes sub-transmitting signals corresponding to the first main control switch, the second main control switch and the target freewheeling switch respectively;

[0193] The logic gate circuit 105 includes an adjustment circuit and a wave blocking control circuit; wherein...

[0194] The adjustment circuit is used to perform logical operations on each of the sub-wave signals, and output a first control signal to the blocking control circuit and a second control signal to the target freewheeling diode. The first control signal and the sub-wave signal corresponding to the second main control diode are not the same as the conduction control signal, and the first control signal and the second control signal are not the same as the conduction control signal.

[0195] The wave blocking control circuit is used to shield the first control signal and control the first main control tube to turn off when it receives the wave-by-wave current limiting trigger signal, and to output the first control signal to the first main control tube when it receives the first safety signal.

[0196] In some embodiments, it also includes:

[0197] In response to the overcurrent protection trigger signal output by the second trigger circuit 106 in the protection circuit, the blocking signal corresponding to the power conversion circuit 102 is output to the logic gate circuit 105. The logic gate circuit 105 is also used to control the main control switch and the freewheeling switch to be turned off in response to the blocking signal.

[0198] The second trigger circuit 106 is used to output the overcurrent protection trigger signal when the sampled signal characterizes that the overcurrent protection condition is met.

[0199] In some embodiments, it also includes:

[0200] In response to the second safety signal output by the second trigger circuit 106, the wave signal is continuously output;

[0201] The second trigger circuit 106 is used to output the second safety signal when the sampled signal indicates that the overcurrent protection condition is not met.

[0202] In some embodiments, the second trigger circuit 106 includes a second comparison circuit and a one-way conduction circuit, wherein,

[0203] The first terminal of the unidirectional conduction circuit is connected to the output terminal of the second comparison circuit, and the second terminal of the unidirectional conduction circuit is used to input a preset voltage and serve as the output terminal of the second trigger circuit 106.

[0204] The second comparison circuit is used to output a reference voltage based on the comparison result between the sampled signal and the second threshold interval;

[0205] When the reference voltage is less than the preset voltage, the unidirectional conduction circuit is turned on, and the second trigger circuit 106 outputs the overcurrent protection trigger signal;

[0206] When the reference voltage is greater than or equal to the preset voltage, the unidirectional conduction circuit is turned off, and the second trigger circuit 106 outputs the second safety signal.

[0207] In another embodiment of this application, an electronic device is also provided, including at least one processor and at least one memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, it implements the protection control method as described in any of the above embodiments.

[0208] In addition to the methods and devices described above, the protection control method provided in the embodiments of this application can also be a computer program product, which includes computer program instructions. When the computer program instructions are run by a processor, they cause the processor to perform the steps in the protection control method according to various embodiments of this specification as described in the "Exemplary Methods" section above.

[0209] Computer program products can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments described herein. Programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on a semiconductor process device, partially on the device, as a standalone software package, partially on a semiconductor process device and partially on a remote semiconductor process device, or entirely on a remote semiconductor process device or server.

[0210] Furthermore, embodiments of this specification also provide a computer-readable storage medium having a computer program stored thereon, the computer program being executed by a processor of the steps in the protection control methods according to various embodiments of this specification as described in the "Exemplary Methods" section above.

[0211] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this specification can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0212] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0213] The embodiments described above are merely illustrative of several implementation methods outlined in this specification. While the descriptions are specific and detailed, they should not be construed as limiting the scope of the solutions provided in this specification. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this specification, and these all fall within the scope of protection of this specification. Therefore, the scope of protection for this patent should be determined by the appended claims.

Claims

1. A protection circuit, characterized in that, include: The sampling circuit is used to sample the current of the energy storage inductor in the connected power conversion circuit and output the sampling signal. The first trigger circuit is used to output a wave-by-wave current limiting trigger signal when the sampled signal characterization satisfies the wave-by-wave current limiting condition; The controller is used to output the transmission signal corresponding to the power conversion circuit; A logic gate circuit is used to drive the main control switch in the power conversion circuit to turn off in response to the wave-by-wave current limiting trigger signal, and to drive the freewheeling switch in the power conversion circuit to operate based on the wave signal.

2. The protection circuit according to claim 1, characterized in that, The controller is also used for: Count the cumulative number of times the wave-by-wave current limiting trigger signal is received within the current counting period; When the cumulative number of times reaches a preset number, the blocking signal corresponding to the power conversion circuit is output; The logic gate circuit is also used to control both the main control switch and the freewheeling switch to turn off in response to the blocking signal.

3. The protection circuit according to claim 2, characterized in that, The controller is also used for: The wave signal is continuously output when the cumulative number of times has not reached the preset number of times.

4. The protection circuit according to claim 1, characterized in that, The first trigger circuit is specifically used for: When the sampled signal indicates that the current limiting condition is met, the current limiting trigger signal is continuously output for a preset duration.

5. The protection circuit according to claim 4, characterized in that, The first trigger circuit is also used for: When the sampled signal does not meet the wave-by-wave current limiting condition and the current time is not within the preset duration, a first safety signal is output. The logic gate circuit is also used to respond to the first safety signal and drive the main control switch and the freewheeling switch to operate based on the wave signal.

6. The protection circuit according to claim 5, characterized in that, The first trigger circuit includes a first comparison circuit and a timer. The input terminal of the first comparison circuit serves as the input terminal of the first trigger circuit, and the output terminal of the timer serves as the output terminal of the first trigger circuit. The first comparison circuit is used to output a comparison signal to the timer based on the comparison result between the sampled signal and the first threshold interval; The timer is used to continuously output the wave-by-wave current limiting trigger signal for a preset duration when the comparison signal indicates that the sampled signal exceeds the first threshold interval, and to output the first safety signal when the comparison signal indicates that the sampled signal does not exceed the first threshold interval and the current time is not within the range of the preset duration.

7. The protection circuit according to claim 6, characterized in that, The comparison signal includes a first transition signal that transitions from a first level to a second level. The timer responds to the first transition signal and continuously outputs the wave-by-wave current limiting trigger signal within the preset duration. The first level signal indicates that the sampled signal has not exceeded the first threshold range, and the second level signal indicates that the sampled signal has exceeded the first threshold range. The comparison signal also includes the first level or a second transition signal that transitions from the second level to the first level. When the timer is not within the range of the preset duration at the current time, it responds to the first level or the second transition signal and outputs the first security signal.

8. The protection circuit according to claim 5, characterized in that, The main control switch includes a first main control switch and a second main control switch, the freewheeling switch includes a target freewheeling switch, the target freewheeling switch and the first main control switch are complementaryly connected, the second main control switch is kept off, and the wave transmission signal includes sub-wave transmission signals corresponding to the first main control switch, the second main control switch and the target freewheeling switch respectively; The logic gate circuit includes an adjustment circuit and a wave blocking control circuit; wherein... The adjustment circuit is used to perform logical operations on each of the sub-wave signals, and output a first control signal to the blocking control circuit and a second control signal to the target freewheeling diode. The first control signal and the sub-wave signal corresponding to the second main control diode are not the same as the conduction control signal, and the first control signal and the second control signal are not the same as the conduction control signal. The wave blocking control circuit is used to shield the first control signal and control the first main control tube to turn off when it receives the wave-by-wave current limiting trigger signal, and to output the first control signal to the first main control tube when it receives the first safety signal.

9. The protection circuit according to any one of claims 1 to 8, characterized in that, Also includes: The second trigger circuit is used to output an overcurrent protection trigger signal when the sampled signal characterizes that the overcurrent protection condition is met. The controller is also configured to respond to the overcurrent protection trigger signal by outputting a blocking signal corresponding to the power conversion circuit; The logic gate circuit is also used to control both the main control switch and the freewheeling switch to turn off in response to the blocking signal.

10. The protection circuit according to claim 9, characterized in that, The second trigger circuit is also used for: When the sampled signal does not meet the overcurrent protection conditions, a second safety signal is output. The controller is also configured to continuously output the wave signal in response to the second safety signal.

11. The protection circuit according to claim 10, characterized in that, The second trigger circuit includes a second comparator circuit and a one-way conduction circuit, wherein, The first terminal of the unidirectional conduction circuit is connected to the output terminal of the second comparison circuit, and the second terminal of the unidirectional conduction circuit is used to input a preset voltage and serve as the output terminal of the second trigger circuit. The second comparison circuit is used to output a reference voltage based on the comparison result between the sampled signal and the second threshold interval; When the reference voltage is less than the preset voltage, the unidirectional conduction circuit is turned on, and the second trigger circuit outputs the overcurrent protection trigger signal; When the reference voltage is greater than or equal to the preset voltage, the unidirectional conduction circuit is turned off, and the second trigger circuit outputs the second safety signal.

12. A power converter, characterized in that, It includes a power conversion circuit and a protection circuit as described in any one of claims 1 to 11.

13. A protection and control method, characterized in that, The method, applied to a protection circuit as described in any one of claims 1 to 11, comprises: Output the waveform signal corresponding to the power conversion circuit connected to the protection circuit to the logic gate circuit in the protection circuit; The logic gate circuit is used to drive the main control switch in the power conversion circuit to turn off in response to the wave-by-wave current limiting signal output by the first trigger circuit in the protection circuit, and to drive the freewheeling switch in the power conversion circuit to operate based on the wave signal; the first trigger circuit is used to output the wave-by-wave current limiting trigger signal when the sampling signal output by the sampling circuit in the protection circuit indicates that the wave-by-wave current limiting condition is met, and the sampling circuit is used to sample the current of the energy storage inductor in the power conversion circuit and output the sampling signal.

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